//Instantiate Presentation class that represents a presentation file
Presentation pres = new Presentation("data/presentation.pptx");

//Clone the desired slide to the end of the collection of slides in the same presentation
ISlideCollection slds = pres.getSlides();

//Clone the desired slide to the specified index in the same presentation
slds.insertClone(2, pres.getSlides().get_Item(1));